Any Suggestions

First topic message reminder :

2yr old Nelson conversion on a dedicated frame built for the Nelson with GSG mags.  The gun had worked flawlessly until about 3 months ago when it started failing to chamber the 2nd round in the magazine. Sometimes it will be more than just the 2nd round but mostly the 2nd round.

I have replaced the recoil spring, all mag springs and even purchased a couple new GSG mags and the problem persists. Dirty chamber, breach face not the problem.

Problem occurs with all brands of SV ammo.  I don't shoot HV ammo in the gun.  I have an Nelson with iron sights and the problem occurs with the slide from that unit also.

Some times I can prevent the problem by keeping the mags in my pocket but cold should not be an issue at an indoor range and the problem stated outdoors when the temps were in the low to mid 70's

Any Suggestions?

Not a gunsmith but I would take the main spring housing apart and see
if there is any crud or any sign of scratching of components. If not clean
and oil. May not correct but won't hurt. I do this on all my gun ever so
often.
Lamar H